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      03-09-2013, 04:07 PM   #114
COBodom
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Quote:
Originally Posted by Boss330 View Post
Note that I didn't say that they care more about their car, but that they probably care more about THAT ASPECT of their car.

When I mentioned the 5 cylinder cars I didn't think of the V5 VAG engine (forgot about that one) but the Audi and Volvo inline 5 cyl engines. Those engines have a sweet sound and refinement.

The difference between a V and inline engine is much more than just nomenclature. It's the basic design of the engine that's different, and therefore also the characteristics of the engine.

For instance:
Due to the odd number of cylinders in each bank, V6 designs are inherently unbalanced, regardless of their V-angle. Each cylinder bank in a V6 has an odd number of pistons, so the V6 also suffers from the same problem unless steps are taken to mitigate it. In the horizontally opposed flat-6 layout, the rocking motions of the two straight cylinder banks offset each other, while in the inline-6 layout, the two ends of engine are mirror images of each other and compensate every rocking motion.

The straight-six layout is the simplest engine layout that possesses both primary and secondary mechanical engine balance, resulting in much less vibration than engines with fewer cylinders.

The poor secondary harmonic balance of four-cylinder engines is largely addressed with the use of balance shafts although it can never match the in-line six.

An inline six engine is in perfect primary and secondary mechanical balance, without the use of a balance shaft. The engine is in primary couple balance because the front and rear trio of cylinders are mirror images, and the pistons move in pairs (but of course, 360° out of phase and on different strokes of the 4-stroke cycle). That is, piston #1 mirrors #6, #2 mirrors #5, and #3 mirrors #4, largely eliminating the polar rocking motion that would otherwise result. Secondary imbalance is avoided because the crankshaft has six crank throws arranged in three planes offset at 120°. The result is that the secondary forces that are caused by differences from purely sinusoidal motion sum to zero.

An inline four cylinder or V6 engine without a balance shaft will experience secondary dynamic imbalance, resulting in engine vibration. As a general rule, the forces arising from any dynamic imbalance increase as the square of the engine speed — for example, if the speed doubles, vibration will increase by a factor of four. In contrast, inline six engines have no primary or secondary imbalances, and with carefully designed crankshaft vibration dampers to absorb torsional vibration, will run more smoothly at the same crankshaft speed (rpm). This characteristic has made the straight-six popular in some European sports-luxury cars, where smooth high-speed performance is very desirable.

http://en.wikipedia.org/wiki/Straight_engine
http://en.wikipedia.org/wiki/V_engine
http://en.wikipedia.org/wiki/V6_engine
http://en.wikipedia.org/wiki/Inline-6

As you can see it's not just some peoples personal opinions about the difference between a i4 and a i6 (or between a i6 and a V6). It's actually down to physical and mechanical properties of the the different configurations.

Most people wont care or notice (my wife would not know or appreciate the difference between a 4 or 6 cyl engine), but for me that's one of the key factors in owning a BMW. And I know there IS a difference. I could also live with a 328i (and enjoy the experience), but I would know that the i4 engine is there because of gas mileage and that the sound and feel of the engine can't match that of the BMW i6 engine. No 4 cyl engine can, due to it's inherent design characteristics.
Appreciate the copy/paste.

I didn't say nomenclature was the only difference. I said that you are correct on the proper nomenclature. Not sure where you got the idea that I am claiming nomenclature being the only difference. Of course there are mechanical and physical differences. I never said there aren't.

We can keep going on and on about those personal preferences and whether you hear/feel the difference in engines. Folks who want a V6 to begin with shouldn't even test drive the four; they will never be happy with the four banger. It has nothing to do with performance, but more with the aforementioned personal preference.

As far as performance goes, a four banger can outperform a v6 as it has been proven many times (i.e 2011 528 vs 2012).

Please note that Audi is a VAG car too.
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